A Virtual Private Network (VPN) is a private network generally used by companies to transfer data over a public network. VPN packets are transferred over public networks such as the Internet using standard and typically insecure protocols. There are usually two components to a VPN, a secure internal network and an unsecure outside network. Secure networks are also referred to as private networks and unsecure networks are referred to as public networks. A firewall or some sort of security implementation is implemented between the internal network and the outside network to maintain security within the internal network. The firewall seeks to limit access to the internal network to those users with permission.
Attempts have been made to ensure that VPNs are secure. Some secure VPNs use cryptographic tunneling protocols to provide a number of security measures such as confidentiality to prevent snooping, sender authentication to prevent identity spoofing and message integrity to ensure messages are not manipulated. Tunneling allows data which is intended for a private network to be sent through a public network without the nodes of the public network knowing the data belongs to a private network. Tunneling is implemented by encapsulating the private network data and protocol information within public network transmission units so that the private network protocol information appears to be regular data to the public network. When implemented properly, VPNs like these create a relatively secure communication medium over unsecured networks.
Some VPNs rely on users to be secure by implementing spyware and virus scanners. These VPNs even check occasionally whether the spyware and virus scanners have been installed and are very limited in the efforts made to secure the network. However, if a user's device is not properly configured, the entire VPN's security could be compromised.